Mature colonies of leaf-cutting ants (LCA) in the genus Atta are among the largest of any social insect. These “superorganisms” harvest substantial amounts of leaf material per year, which they use to cultivate a specialized symbiotic fungus for food (Basidiomycota, Agaricales, Leucoagaricus). This complex symbiosis is not bipartite as originally thought, as it includes at least four coevolved and integrated organisms: the farming ants, the fungi that the ants cultivate for food, a genus of fungi (Escovopsis) that are specialized mycoparasites of the ant’s fungal gardens, and actinomycete bacteria (genus Pseudonocardia) that the ants culture on their bodies and from which they obtain antibiotics against the Escovopsis parasites. More recently we described an additional symbiosis with Nitrogen-fixing bacteria that colonize the fungus gardens and contribute to supplement the ants’ nutrition. Our present research efforts in Costa Rica focus on potential biotechnological application of the ants’ microbial symbionts, including bioprospecting for novel antibiotics. We currently investigate the contributions of symbiotic bacteria in cellulose degradation within the fungus garden, employing a combination of culture-dependent and independent techniques coupled with ultrastructural analysis based on high resolution microscopy. Further, given that the ants constitute one of the main agricultural pests in Latin America, we study microbial parasites of both the ants and the fungus gardens to develop biocontrol products that can be incorporated into Integrated Management Strategies to control the detrimental effects of these insects.

• Adrián Pinto-Tomás(Biochemistry Department, School of Medicine and Center for Research in Microscopic Structures, University of Costa Rica, Costa Rica)